There are more than 27,000 Subway stores in the U.S. alone which means this shift signals a change not just for consumers but for the industry that supplies it.

“Given the size and scope of the Subway brand, this commitment is the largest of its kind in the restaurant industry,” said Dennis Clabby, Subway’s executive vice president of purchasing.

The restaurant has set a timeline for the change in the U.S.:

• Chicken will be completed by the end of 2016.• Turkey will be introduced in 2016, with a completed transition expected within 2-3 years.• Pork and Beef will be completed in 2025.

“A change like this will take some time, particularly since the supply of beef raised without antibiotics in the U.S. is extremely limited and cattle take significantly longer to raise. But, we are working diligently with our suppliers to make it happen,” said Clabby.

The supply challenge may be one reason Subway’s announcement is just happening in the U.S. not in Canada. A spokeswoman told Global News, “the brand will be in touch when a Canada-specific timeline is available to share.”

Subway joins a list of other restaurants that are providing or changing ingredients to keep up with consumer demand. Chipotle and Panera already say they serve meat raised without antibiotics, and McDonald’s said earlier this year it would make a switch for its chickens and offer cage-free chicken eggs.

McDonald’s buys close to two billion eggs a year. Currently in the United States and Canada more than 95 per cent of eggs are still produced in caged housing, according to the Humane Society of the United States, the change, if fully implemented, will impact “nearly eight million animals per year”.

Chickens in their cages in this file photo.

Marcio Jose Sanchez/AP

“Seismic shift in the industry.”

Consumer advocacy and animal rights group Friends of the Earth called Subway’s announcement a game-changer.

“We are excited to see the world’s largest restaurant chain take this game-changing step that will create a seismic shift in the industry,” said Kari Hamerschlag, senior program manager with Friends of the Earth.

The group adds it hopes this will lead to more humane pasture-based livestock systems and a move away from “factory farming.”

“You are looking at 27,000 outlets which is significant, so I would say that 10 years really is the minimum,” said Charlebois, “you really need 10 years to not only realign your supply chain practices, but you need to make sure production capacity goes along with your supply chain strategy. “

Charlebois hopes food companies will recognize farmers will need assistance with the transition both financially and with guidance.

Subway’s announcement comes as multiple groups including Natural Resources Defence Council, Friends of the Earth, the Center for Food Safety, U.S. Public Interest Research Group and food blogger Vani Hari known as the Food Babe, had campaigned to get Subway to commit to buying meat produced without the routine use of antibiotics, and provide a timeline for doing so.

According to Charlebois, “the voice of the consumer is a game changer.”

The ability for consumers to mobilize using social media has put a new type of pressure on companies. McDonald’s said they heard their customers, and understand that animal welfare is a priority.

“They have had an impact, a significant impact and that is why animal welfare has so much currency today, and that is why we are seeing a lot of chains complying to market demands like this, so quickly.”

Antibiotics are approved for use in Canada and the United States for food producers.

They can be used in feed and to prevent illnesses. The practice has become a public health issue, with officials saying it can lead to antibiotic resistance, and concerns they’re no longer effective in treating illnesses in humans.

Subway hopes other food companies will follow its antibiotic-free policy.

“We hope that this commitment will encourage other companies in our industry to follow our lead, and that, together, this will drive suppliers to move faster to make these important changes for consumers,” said Clabby.